Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in Plan Assets:
Employer contributions	$ 25
Amounts Recognized in the Consolidated Balance Sheets:
Pension and other benefit liabilities	(1,566)	$ (1,707)
Post-retirement medical benefits	(340)	(352)
Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation - ending	10,906
Change in Plan Assets:
Fair value of plan assets -beginning	8,878
Employer contributions	139
Fair value of plan assets - ending	10,001	8,878
Net Funded Status	(905)
Other Postretirement Benefits Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation - beginning	385	385
Service cost	2	2	$ 4
Interest cost	12	15	23
Plan participants' contributions	10	10
Actuarial loss	4	8
Currency exchange rate changes	3	5
Plan Amendments/Curtailments	(11)	0
Benefits paid/settlements	(35)	(40)
Other	0	0
Benefit obligation - ending	370	385	385
Change in Plan Assets:
Fair value of plan assets -beginning	0	0
Actual return on plan assets	0	0
Employer contributions	25	30
Plan participants' contributions	10	10
Currency exchange rate changes	0	0
Benefits paid/settlements	(35)	(40)
Other	0	0
Fair value of plan assets - ending	0	0	0
Net Funded Status	(370)	(385)
Amounts Recognized in the Consolidated Balance Sheets:
Other long-term assets	0	0
Accrued compensation and benefit costs	(30)	(33)
Pension and other benefit liabilities	0	0
Post-retirement medical benefits	(340)	(352)
Net Amounts Recognized	(370)	(385)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss (gain)	(23)	(29)
Prior service (credit) cost	(99)	(164)
Total Pre-tax loss (gain)	(122)	(193)
United States | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation - beginning	3,598	3,234
Service cost	2	2	2
Interest cost	196	218	63
Plan participants' contributions	0	0
Actuarial loss	240	564
Currency exchange rate changes	0	0
Plan Amendments/Curtailments	0	0
Benefits paid/settlements	(289)	(420)
Other	0	0
Benefit obligation - ending	3,747	3,598	3,234
Change in Plan Assets:
Fair value of plan assets -beginning	2,493	2,358
Actual return on plan assets	563	529
Employer contributions	35	26
Plan participants' contributions	0	0
Currency exchange rate changes	0	0
Benefits paid/settlements	(289)	(420)
Other	0	0
Fair value of plan assets - ending	2,802	2,493	2,358
Net Funded Status	(945)	(1,105)
Amounts Recognized in the Consolidated Balance Sheets:
Other long-term assets	0	0
Accrued compensation and benefit costs	(24)	(25)
Pension and other benefit liabilities	(921)	(1,080)
Post-retirement medical benefits	0	0
Net Amounts Recognized	(945)	(1,105)
Accumulated Benefit Obligation	3,747	3,598
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss (gain)	874	1,059
Prior service (credit) cost	(1)	(3)
Total Pre-tax loss (gain)	873	1,056
Foreign Plan | Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation - beginning	6,492	6,007
Service cost	20	22	27
Interest cost	113	153	149
Plan participants' contributions	3	3
Actuarial loss	439	472
Currency exchange rate changes	374	114
Plan Amendments/Curtailments	2	(2)
Benefits paid/settlements	(284)	(270)
Other	0	(7)
Benefit obligation - ending	7,159	6,492	6,007
Change in Plan Assets:
Fair value of plan assets -beginning	6,385	5,729
Actual return on plan assets	637	680
Employer contributions	104	115
Plan participants' contributions	3	3
Currency exchange rate changes	354	135
Benefits paid/settlements	(284)	(270)
Other	0	(7)
Fair value of plan assets - ending	7,199	6,385	$ 5,729
Net Funded Status	40	(107)
Amounts Recognized in the Consolidated Balance Sheets:
Other long-term assets	617	451
Accrued compensation and benefit costs	(24)	(22)
Pension and other benefit liabilities	(553)	(536)
Post-retirement medical benefits	0	0
Net Amounts Recognized	40	(107)
Accumulated Benefit Obligation	7,018	6,326
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss (gain)	1,471	1,462
Prior service (credit) cost	27	22
Total Pre-tax loss (gain)	$ 1,498	$ 1,484